The present invention relates to a new and improved construction of a collapsible on-loading and off-loading ramp or the like -- hereinafter usually simply referred to as a collapsible loading ramp -- comprising two spaced substantially parallel longitudinal supports secured to a vehicle, such as a vehicle platform, each support having a ramp portion which can be adjusted and locked in its adjusted position relative to the plane of the platform and an on-loading portion hingedly connected with the ramp portion.
There is already known to the art a loading bridge or ramp from German patent publication No. 1,243,588 which embodies a bridge or ramp body provided at one side with an angle member and at the other side with a channel-shaped transverse groove. At the ramp body there is hingedly connected an on-loading plate having a cylindrical bead engaging in the transverse groove. This loading ramp serves to bridge the intermediate space between a ramp and a vehicle or between two vehicles. If desired, it also can compensate relatively small elevational differences existing between the parts which are to be bridged, since the on-loading plate hinged and bearing at the vehicle platform can be accommodated as a function of the elevational difference with respect to the bridge portion bearing by means of the angle member upon the ramp.
Additionally, there is also known to the art from German publication No. 606,127 an on-loading ramp for vehicles, especially for rail-bound vehicles, which encompasses an upper ramp having suspension pins and formed by two longitudinal supports interconnected by transverse reinforcement members as well as an on-loading portion likewise formed of two longitudinal supports interconnected by transverse reinforcement members. The upper ramp and the on-loading portion are articulated to one another. Owing to the specially constructed hinge shafts, compensation of track irregularities, both in the horizontal as well as in the vertical direction, is possible for the ramp portions bearing upon the tracks.
According to German Pat. No. 1,243,534, there is disclosed a platform vehicle for the transport of relatively heavy equipment or units, wherein at an end portion of the platform there is provided to both sides a respective ramp portion articulated at a horizontal pivot pin and having an on-loading portion hingedly connected with such ramp portion. The ramp portion and the on-loading portion bearing upon the ground are in alignment with one another in the on-loading position of the unit. Further, at the ramp portion there is pivotably mounted an angle lever at which there is hingedly connected at one side a floor support and at the other side a pressure cylinder mounted at the end portion of the platform. By actuating the pressure cylinder the ramp portion together with the equipment or other load located thereon, is brought from the on-loading position into a position aligned with the platform so that the equipment thereafter can be pushed or driven onto the platform without the need for any complicated additional structure. In the travel position of the vehicle the ramp portion is rocked into an approximately vertical position, whereas the on-loading portion, due to its inherent weight, is rocked about the pivot pin and bears against the ramp portion.